Method of puddling



Patented Dec. llll, 11923), I

UNHTED stares HENRY 1D. HIBBARD, F PLAINFIELD, NEW JERSEY, ASSIGNOR TOEIIBBARD PROCESS CORPORATION, O1? NEW YORK, N. i(., A CORPORATION OF NEW JERSEY.

METHOD OF PUDJDLING.

No Drawing.

Union and State of New Jersey, have invented Certain new and useful Improvements in Methods of Puddling, of which the following is a specification.

My invention relates to a method of producing wrought iron, and the object of my method is to produce wrought iron in such manner that the hand operations hitherto commonly practiced are dispensed with, the reactions effected more completely, expeditiously and evenly throughout the mass, a larger and more compact bloom or ball obtained, as well as one better shaped for introduction into the usual squeezer, and. in general to produce the desired product by operations which permit the output of a plant to be greatly increased in quantity, improved in quality and at a materially reduced expense.

Tn the production of wrought iron by puddling, the puddling operations are commonly carried out by manual labor of the severest character under the most trying conditions; the output is necessarily restricted by the limitations of human strength and endurance, the product is nonuniform in chemical composition," andeven the most experienced and powerful operators produce a ball of relatively small size and objectionably spongy character.

The present method, which my investigations have proved to be thoroughly practical, involves operations which are best carried out mechanically, thus obviating many of the dilliculties which have hitherto stood in the way of large output, rapid chemical reaction, and uniformity of product.

I The refining and decarburizing of the charge from which wrought iron is, to be produced, is accomplished by a reaction between the non-ferrous elements of the molten iron and a suitable oxidizing reagent, commonly in the form of an immis cible oxidizing slag of lower specific gravity than that of the metal of the bath. The manual stirring operation heretofore com: monly practiced brings the molten metal 'into contact with the slag blanket, very slowly and very imperfectly. T have found that a much more intimate contact between Application filed September 16, 1921. Serial No. 501,139.

the slag and molten iron can be effected by pouring the charge from one container into another, and so on repeatedly, the arrangement being such of course as to exclude air from the reacting elements so far as possible. On pouring, the slag, being on top, is the first to enter the receiving container, and is followed by the molten metal which thus passes down through the slag in a more or less fine stream Or sheet, or in divided condition, so that practically every part of the metal contacts with the slag on each pour. I prefer to so shape the containers that the charge passes from one container into the other in the form of a sheet of molten metal,in efi ect like a waterfall, the reagents being brought into intimate contact, and churned together at the foot of the fall in the receivin container. The reaction between the s ag and the charge is thus completed very rapidly and uniformly throughout the mass.

The precise manner in which the charge is formed may vary. it prefer to introduce the metal (for example pig or cast iron, or a mixture thereof with steel scrap) in molten condition, into a container which may be. one of a series of compartments in an oscillatoryor rotary furnace of the re verberatory type. The metal may, however, be introduced cold and be melted in the container. Either before or after the metal is charged into the container, an oxidizing reagent, such as oxide of iron, is also introduced into the same, or another container of the series-preferably the same container, and preferably in molten condition.

The reaction which ensues is at first exothermic, and is suiiiciently energetic to maintain the reaction temperature during the oxidation of the major portion of the silicon, phosphorus and manganese in the metal. As the reaction progresses, however, it becomes endothermic, and heat must be supplied to maintain the requisite temperature to the end of the treatmentrthat is to say. until sutficient carbon has been eliminated to satisfy the requirements of the desired product As the elimination of 'the carbon proceeds, the fusion polnt of the iron rises, with the result that the pure iron solidifies in-the bath and separates in solid, or. vsemi-solid, particles, or as is familiarly termed comes to nature.

As the charge is poured again and again from one container to another, the'solid particles gather together, the temperature being now increased, if necessary, to bring the pure metal to Welding temperature; The mass of iron rapidly increases in size by the welding together of the gathered clusters of grains under the impact of their fall from one container to another.

While thus gathering together into a ball or bloom, the purified iron entrains into the solidified mass, .more or less of the slag. This, however, is. to aconsiderable extent expressed by the impact of the ball against the bottoms of the containers as the pouring operation is continued, and the ball is thus compacted and the slag partially eliminated. This operation may be repeatedas often as desired to efi'ect as complete an expulsion of the slag as may be deemed. necessary.

The ball may then be discharged to the squeezer or it may be rolled back and forth in one of the containers until it-has assumed an v elongated, cylindrical or spindle-like P shape, better adapted for the action of the squeezer in further eliminating therefrom the entrained slag. Of course in discharging' the ball it will be understood that the still fluid slag is first poured from the container, after which the ball is discharged.

ltn making iron of superior quality. it is advisable to utilize two slags, the first being poured off after the bulk of the silicon, phosphorus and manganese, and a considerable part of the sulphur contained in the iron, have been eliminated. After this slag has been -poured ofi, fresh oxidizing material, such as a further quantity of oxide of iron, is-introduced to effect the oxidation of the carbon. Preferably a thin, such "as silica or fluorspar, is added. which ,will tend to lower the fusion point of the slag cinder so that it may be freely discharged in advance of the ball. The pouring operation is of course repeated with the second slag in contact with the iron, just as in the treatment with the first slag. After the purification of the metal is thus completed the ball may be compacted and shaped in the same manner as above described, the slag in each case. being preferably retained until the ball is ready for discharge, after which it is poured ofi in advance of the ball. 1

The apparatus in which the method thus described may be carried out is subject to many modifications. I prefer, however, a reverberatory furnace of the general type shown in my Patent No. 1,362.532, Decem ber 14, 1920, or in may copending application Serial No. 468,709, filed May 11. 1921. It will be obvious that the de tails of the process will vary with the material under treatment, and with the character of the wrought iron which it is desired to produce; The temperature atnraeae which the process is carried on does riot vary from that ordinarily employed in puddling processes, although ll am not aware that it has heretofore been proposed to utilize alone case in an ordinary hand-operated p uddling furnace. Moreover the thorough and intimate contact between the reagents etl'ected by the pouring-through operation of the present method not only renders the reaction more uniform and complete throughout the mass, but greatly expedites the treatment. This will bethe more readily recognized when it is" considered that chemical action between two immiscible fluids, or any of their ingredients, can take place only at the surfaces where they are in contact with each other. If they are quiescent, that is to say, one lying on the other, that surface is a horizontal plane. llf mixed however, the

contact surface area between two immiscible liquids is greatly-increased and the reaction expedited accordingly.

The repeated impact of the ball against the bottoms of the containers produces a ball which retains far less slag than the usual hand-puddled ball, while its eventual shaping in the container before it is discharged fits the product for the most efiicient action of the squeezer thereon in further eliminating the entrained slag.

ll claim as'my inventioni l. The process of promoting chemical reaction between certain components of immiscible molten fluids of different specific gravities, which comprises repeatedly pouring said fluids together from one container into another, and under temperature conditions such that one of the fluids eventually solidifies as a result of the rise of its fusion temperature incident to a chemical change therein caused by the reaction.

2. The method of producing wrought iron which comprises the step of repeatedly pouring molten iron and oxidizing slag from one container to another under temperature conditions such that upon the elimination by oxidation of substantially all the non-ferrous elements "of the iron the latter collects as a ball or bloom while the slag remains in a molten state.

3. The method of producing wrought iron which comprises the step of repeatedly pouring molten iron and oxidizing slag from one container to another under temperature conlltll) inmate rous elements of the iron the'latter collects till as a ball or bloom while the slag remains in a molten state, and thereafter continuing to pass the ball or bloom from one container to gnpther to expel entrained slag from the 4:. The method of producing wrought iron which comprises the step of repeatedly pouring molten iron and oxidizing slag from one container to another under temperature conditions such that upon the elimination by oxidation of substantially all the non-ferrous elements of the iron the latter collects as a ball or bloom while the slag remains in a molten state, and thereafter repeatedly dropping the bloom to expel therefrom entrained slag. p

5. The method of producing wrought iron which comprises the step of repeatedly pouring molten iron and oxidizing slag from one container to another under temperature conditions such that uponthe elimination by oxidation of substantially all the non-ferrous elements of the iron the latter collects as a ball or bloom while the slag remains in a molten state, and thereafter rolling the bloom while in contact with the slag to shape the bloom. 7

6. The method of producing wrought iron which comprises the step of repeatedly pouring molten iron and oxidizing slag from one container to another under temperature conditions such that upon the elimination by oxidation of substantially all the non-ferrous elements of the iron the latter collects as a ball or bloom-while the slag remains in a molten state, and thereafter continuing to pass the ball or bloom from one container one container to another, and supplying heat, after the reaction has become endothermic, to maintain the reaction temperature until the non-ferrous elements in the molten iron have been substantially eliminatcd and the iron comes to nature and gathers in a bloom or ball.

8. The method of reducing Wrought iron which comprises c arging molten iron and oxidizing slag into a container, promoting the exothermic reaction between the same by pouring the same repeatedly from one container to another, and supplying heat, after the reaction has become endothermic, to maihtain the reaction tempera-' ture until the non-ferrous elements in the molten iron have been substantially eliminated and the iron comes to nature and gathers in a bloom or ball, and thereafter by gravity impact expelling entrained slag from the bloom. T

9. The method of producing wrought iron which comprises partiallyrefining molten iron by the heat of an exothermic reactionwith an oxidizing slag, pouring off at least portion of the slag with its contained impurities, adding a fresh quantity of oxidizing material-and supplying heat to maintain theendothermic reaction between this slag and the molten metal during the remainder of the refining treatment. 10. In the manufacture of wrought iron, the step of repeatedly dropping the bailed metal while in contact with molten slag, to compact the ball and eliminate entrained slag therefrom.

11. m the manufacture'of wrought iron, the step of repeatedly droppin the balled metal while in contact with mo ten slag, to compact the ball and eliminate entrained slag therefrom, and thereafter shaping the ball by'rolling the same before the slag is run ofi.

12. The method of operating an oscillating puddling furnace having a dam over which the charge may be poured back and forth, which method consists in oscillating the furnace during the progress of the puddling reaction to cause the charge to pour back and forth over the top of the dam, and after the reaction is complete oscillating the furnace in such angular position that the charge is rolled back and forth on the hearth of the basin, but to one side of the dam, to shape the product.

13. The method of operating an oscillating puddling furnace having a dam over which the charge may be poured back and forth, which method consists in oscillating the furnace during the progress of the pod. dling reaction to cause the charge to pour back and forth over the top of the dam, and after the reaction is complete, oscillating the furnace in such angular position that. the charge is rolled back and forth on the hearth of the basin, but to one side of the dam to shape the product, and finally tilting the basing to discharge the thus shaped product.

14. The method of puddling iron which consists in reacting molten iron and an oxidizing agent, to remove from the iron the bulk of the silicon, phosphorus and manganese therein contained, pouring ofithe slag resulting, from this reaction, introducing a further quantity of an oxidizing agent and heating the charge to effect the combination of the carbon therein with said oxidizing agent, and discharging the thus purified iron. Y

15. The method of puddling iron which v further consists in reacting molten iron and an oxidizing agent, to remove from the iron the bulk of the silicon, phosphorus and manganese therein contained, pouring ofi' the slag resulting from this reaction, introducing a quantity of an oxidizing agent, to gether with a suitable flux, and heating the charge to efi'ect the combination of the carbon therein with said oxidizing agent, and discharging the thus purified iron.

16. The steps in the process of producing wrought metal, which consists in alternately pouring a mixture of molten metal and molten oxidizing slag from one receptacle to another and back again until the metalloids and other impurities in the metal be comes freely oxidized, and. then balling the metal into a mass by rolling it in one of the receptacles only.

17. The steps in the process of produc-'.

ing wrought metal, which consists in alternately pouring a mixture of molten metal and molten oxidizing sla from one receptacle to another and ban again until the metalloids and other impurities in the metal become freely oxidized, supplying sufficient external heat to the mixture to maintain the reaction, and. then balling the metal into a Ipass by rolling it in one of the receptacles on y.

In testimony whereof I have signed my name to this specification.

HENRY D. HIBBARD. 

